1. Field of the Invention
The present invention relates to a high-pressure treatment apparatus for reacting and treating an object to be treated such as organic radioactive waste such as, for instance, ion exchange resin used at atomic power plants with a medium such as, for instance, water, oxygen or the like under high-pressure. To be more specific, the present invention relates to a high-pressure treatment apparatus using a medium in a sub-critical or super-critical state. In particular, the present invention relates to, in the aforementioned apparatus, a high-pressure reactor for reacting therein an object to be treated and a medium under a high-pressure, a feeder for feeding the object to the high-pressure reactor and a feeding method thereof, and a method for protecting the high-pressure reactor.
2. Description of the Related Art
In recent years, a technology for reacting in water under high pressure and high temperature exceeding the critical point of water (temperature: 374xc2x0 C., pressure: 22 MPa), a technology for reacting in carbon dioxide under high pressure and high temperature exceeding the critical point of carbon dioxide (temperature: 31xc2x0 C., pressure: 7.38 MPa) and a technology for reacting in hydrocarbons under high-pressures exceeding critical points of various kinds of hydrocarbons are well known. By making use of such super-critical fluids, the following effects can be obtained (for instance, Caruana, C. M.: Chem. Eng. Prog., 4, 10 (1995), Erickson, J. C., P. Schyns, and C. L. Cooney: AlChE J., 36, 299 (1990), and Jezko, J., D. Gray, and J. R. Kershaw: Fuel Processing Technology, 5, 229-239 (1982)).
(1) With only a small pressure change, a large density change can be obtained. In general, solubility of substance varies in proportion to the density thereof. Accordingly, a large difference of solubility can be obtained by changing pressure only. This property can be applied in extraction and separation.
(2) Super-critical fluid, though the density thereof is similar to that of liquid, is low in viscosity thereof and high in diffusion thereof. Accordingly, the super-critical fluid is more advantageous than liquid from a viewpoint of mass transfer, resulting in a large rate of reaction.
(3) Thermal conduction of super-critical fluid is remarkably high. Accordingly, reaction temperatures can be controlled with ease.
Recently, an apparatus of decomposing organic waste and inorganic waste by use of such sub-critical fluid or super-critical fluid, in particular, super-critical water as a reaction medium is attracting attention. According to this method, in spite of relatively high cost thereof, compared with the case of incinerating, there are advantages that reaction products can be completely decomposed to non-hazardous substances and incineration ashes are prevented from dispersing. Accordingly, this method is considered to apply in decomposition of hazardous organic materials and radioactive wastes.
When processing such substances, safety of an apparatus is the most important problem. It is presumed that high-pressure reactors are not subjected to damage such as corrosion. In addition, the treatment object, in feeding to the apparatus, is required to prevent from leaking outside of the apparatus.
A high-pressure reactor, generally considering corrosion-resistance to reaction media and reaction products, is designed as a pressure vessel having thickness of strength capable of enduring the pressure thereof. Austenite system stainless steel and Ni based alloy that have high-temperature strength and are corrosion-resistant are used in large as typical materials for high-temperature and high-pressure reactors. However, under such an oxidizing condition that the super-critical water contains Clxe2x88x92 or SO42xe2x88x92, it is reported that these are not sufficiently corrosion-resistant and tend to be subjected to corrosion (for instance, D. A. Hazlebeck, K. W. Doeney, J. P. Elliot and M. H. Spritzer, Proc. First Int. Workshop on Super-critical Water oxidation).
As highly corrosion-resistant metallic materials in such an environment, noble metals such as Pt, Au or the like, Ti, Ti alloys, Ta, Ta alloys or ceramics can be considered. However, these materials are expensive compared with generally used steel for pressure-vessel. In addition, some of these are highly corrosion-resistant but too low in strength to be a pressure-vessel by itself. In such cases, they can be used only as covering materials for such as lining and coating.
As a means to these ends, a structure is disclosed in which a high-pressure vessel is built into a double-vessel structure, inside of an exterior pressure vessel a high-pressure vessel as a high pressure reactor is installed, and the pressure within the high-pressure vessel and that of the gap portion therebetween is made equal to be balanced. Thereby, the high-pressure vessel is alleviated from being pressurized too much (for instance, WPI Acc No. 98-057323/199806: Supercritical water oxidation processing (ORGANO CORP)).
In this method, the high-pressure vessel is not required to be highly pressure-resistant but is required only to be corrosion-resistant. Accordingly, a vessel of thin-walled structure can be adopted. As a result of this, the cost of a vessel can be reduced. In addition, the exterior pressure vessel is not required to be highly corrosion-resistant but required only to be pressure-resistant. Accordingly, various kinds of materials can be adopted to result in cost reduction.
However, it is difficult to foresee completely local damages such as pitting and stress-corrosion cracking. Once such a damage happened, hazardous materials within the high-pressure vessel diffuse into the gap to be likely to contaminate even the exterior pressure vessel.
When it is necessary to heat the high-pressure vessel due to insufficient generation of heat of reaction, ordinarily a heating unit such a heater or the like is arranged outside of the high-pressure vessel. Therewith, the inside of the vessel is heated by making use of the vessel wall as heat conduction medium. However, when there is likelihood of contaminating even the exterior pressure vessel as mentioned above, though the heating unit is necessary to be arranged outside of the exterior pressure vessel, due to existence of pressure-holding medium between the exterior pressure vessel and the high-pressure vessel, heating efficiency becomes extremely low.
In order to make a treatment object react efficiently, it is desirable that feeding amount and feeding speed of the object to the high-pressure vessel can be controlled with ease. From a viewpoint of safety too, such a control is necessary. However, when the treatment objects are solid materials, it is difficult to feed them into the high-pressure reactor of high temperature and high pressure. In particular, it is difficult to feed them continuously.
Within super-critical fluids or sub-critical fluids, reactions of substance proceed faster. Accordingly, if super-critical fluid or sub-critical fluid within the high-pressure vessel penetrates into feeding system in the treatment apparatus, it is likely for the reaction to occur inside of the feeding system.
Such a problem is common not only in the case of feeding solid materials into super-critical fluid but also in the case of feeding into highly pressurized fluid.
Accordingly, it is of great importance to prevent the fluid within a high-pressure vessel from the back flow into a feeding system of an object to be treated.
In FIGS. 17 and 18, conventional feeding systems of feeding solid materials into a high-pressure vessel are shown.
FIG. 17 shows an example of system diagrams, where organic material prepared in slurry are fed into a high-pressure reactor by use of a feed-pump (see U.S. Pat. No. 4,338,199: Processing Method for the Oxidation of Organics in Supercritical Water).
Organic materials fed into a feed slurry tank 11 are mixed with water for adjusting to form slurry. This slurry is fed by use of a feed-pump 15 into an oxidizing reactor 19 through an extractor 17 and is mixed with air or oxygen fed from a raw material source 20 through an oxidant compressor 22 to react under a super-critical state. Reaction products are sent to an ash separator 25 and, after removal of ashes 26, are sent to an expander turbine 28 to proceed to an outlet 30.
Like this technology, in order to feed the solid materials in slurry form to a high-pressure reactor, the solid materials are necessary to be pulverized into powder of a representative diameter of several tens xcexcm or less to mix with fluid. However, fine powder, being likely to be dispersed and to be easily influenced by static electricity, is difficult to handle. In addition, for instance, in the case of plastics, because of hydrophobic property and large difference of density with water, there may be cases where preparation in slurry form is difficult. Further, when a treatment object is ion-exchange resin to which radioactive nuclides were absorbed, pulverizing as pretreatment is equivalent to dispersing contamination. Consequently, it can not be prepared in slurry form.
FIG. 18 shows a conventional example of which melting plastic waste is fed (see Adschiri, T., S. Hirose, and K. Arai: J. Chem. Eng. Japan, 26,676 (1993).
Plastic waste 51, after being melted in a melting bath 52 to which a heat-exchange pipe 54 is installed to form molten plastic 53, is fed to a pre-heater 55. Then, the molten plastic 53 fed to a reactor 56 is mixed with water vapor 58 of high temperature fed from a boiler 57 to be decomposed in a super-critical state. Generated reaction products 59, after cooled by the pre-heater 55, go through a heat exchange pipe 54 of the melting bath 52 to utilize for melting the plastic waste 51. Further, as demand arises, the reaction products are cooled at the heat exchanger 60, followed by sending to a gas-liquid separator 61. Liquid component is sent to a separator 62 and gaseous component is sent to after-processing unit 66.
This technology can only handle solids that can be melted but can not handle coal or thermosetting plastics. This is a problem of the conventional technology.
The present invention is carried out to solve the aforementioned problems that the conventional technology has. A first object of the present invention, so as to process safely and efficiently under a highly corrosive condition of high pressure and high temperature, is to provide a high-pressure treatment apparatus that is excellent in safety and corrosion-resistance and is less expensive.
A second object of the present invention is to provide a method for protecting a high-pressure treatment apparatus having a high-pressure reactor excellent in safety and corrosion-resistance and the high-pressure reactor thereof.
A third object of the present invention is to provide a high-pressure treatment apparatus in which solid, without preparing in slurry form or without melting, is fed intermittently or continuously into a high-pressure reactor, and a method of feeding the treatment object. Further, a fourth object of the present invention is to provide a high-pressure treatment apparatus that, in feeding the treatment object, can certainly prevent the fluid within the high-pressure reactor from flowing backwards toward the feeder, and a feeding method of the treatment object.
In order to accomplish the aforementioned objects, a first high-pressure treatment apparatus of the present invention comprises a first solid reservoir, a second solid reservoir connected to the aforementioned first solid reservoir through a first connecting pipe, a high-pressure, reactor connected to the second solid reservoir through a second connecting pipe, means for feeding reaction medium into the high-pressure reactor, first and second sealing units that are intervened respectively in the first connecting pipe and the second connecting pipe, a first fluid feed unit for feeding a first fluid between the first sealing unit and the second sealing unit, a second fluid feed unit for feeding a second fluid between the second sealing unit and the high-pressure reactor, and means for opening the second sealing unit at the time of shut-off of the first sealing unit and controlling the first and second fluids to form a pressure gradient so that pressure between the first sealing unit and the second sealing unit and pressure between the second sealing unit and the high-pressure reactor decrease gradually towards the high-pressure reactor.
For the first sealing unit and the second sealing unit, for instance, reciprocating switchgears can be used, but without restricting to this, any units that can secure sealing of high-pressure fluid can be used.
As the treatment object, solids that are difficult in preparing in slurry form or difficult in melting can be a treatment objects. For instance, hydrophobic plastic waste, solid wastes that absorb radioactive nuclides, and coal can be cited.
As reactions occurring within a high-pressure reactor, decomposition, oxidation, synthesis, and extraction/separation of substances due to super-critical state or sub-critical state can be cited. However, the reactions are not necessarily restricted to the reactions in the super-critical state or the sub-critical state but can be any reactions under high pressures.
For the reaction media, water, carbon dioxide, hydrocarbons, air, oxygen, or mixtures of two kinds or more thereof can be preferably used. The reaction media is not restricted to these and any one can be selected according to the aimed reactions, treatment objects or the like.
An oxidant can be added to a reaction medium. For instance, in case of decomposition of plastic, an addition of an aqueous solution of hydrogen peroxide as an oxidant to water improves preferably decomposition efficiency.
The first and the second fluids can be appropriately selected according to aimed reactions, the objects being processed or the like. For instance, gases such as air, oxygen gas, carbon dioxide gas, hydrocarbon gases, nitrogen gas, argon gas or mixtures of two kinds or more thereof can be used. In addition, liquids such as water, aqueous solution of hydrogen peroxide, liquid hydrocarbons, or mixtures of two kinds or more thereof can be used.
For instance, in decomposing plastics or burning coal, when air or oxygen is used as the first and the second fluids, reaction efficiency in the high-pressure reactor can be preferably improved. Air can be obtained with ease and an apparatus can be simplified. Accordingly, it is also preferable from a viewpoint of cost.
When the liquid such as water is used, the treatment object can be preferably fed into the high-pressure reactor while washing out the treatment object.
With such a constitution, in feeding a treatment object that is solid into a high-pressure reactor, the fluid can be prevented from back flow from the high-pressure reactor to the second solid reservoir.
The high-pressure treatment apparatus of the present invention, in the first high-pressure treatment apparatus, is characterized in that means for forming the pressure gradient comprises a first pressure adjustment unit for adjusting the pressure of the first fluid, a first flow rate adjustment unit for adjusting a feed amount of the first fluid, a second pressure adjustment unit for adjusting the pressure of the second fluid, and a second flow rate adjustment unit for adjusting a feed amount of the second fluid.
With such a constitution, in feeding a treatment object that is solid into a high-pressure reactor, by causing the fluid to flow always from the second solid reservoir to the high-pressure reactor, the fluid can be firmly prevented from back flow from the high-pressure reactor to the second solid reservoir.
The high-pressure treatment apparatus of the present invention, in the first high-pressure treatment apparatus, is characterized in that a volume of the second solid reservoir is smaller than that of the first reservoir.
The volume ratio of the first solid reservoir and the second solid reservoir is in the range of from 100000 to 2:1, preferably in the range of from 10000 to 10:1, more preferably in the range of from 100 to 10:1. When solid is fed into the high-pressure reactor, though different according to materials for apparatus, temperatures to be used, pressures to be used and so on, a material thickness of the apparatus required to be pressure-resistant is necessary to be made thick. The first solid reservoir is not required to be pressure-resistant. Accordingly, if constituted so that the treatment object is divided in small volumes to transfer from the first solid reservoir to the second solid reservoir of smaller volume, the second solid reservoir required to be pressure-resistant can be made smaller than the existing one, resulting in reduction of apparatus cost.
The high-pressure treatment apparatus of the present invention, in the first high-pressure treatment apparatus, is characterized in that the second solid reservoir comprises a pressure relief valve.
By opening this pressure relief valve, the treatment object can be transferred from the first solid reservoir to the second solid reservoir under atmospheric pressure.
The high-pressure treatment apparatus of the present invention, in the first high-pressure treatment apparatus, is characterized in that the first connecting pipe, the second solid reservoir, the second connecting pipe, the second sealing unit and the high-pressure reactor all of that are installed downstream from the first sealing unit are pressure-resistant.
As mentioned above, in feeding solid into the high-pressure reactor, the apparatus necessary to be pressure-resistant is necessary to be made thick in its wall thickness. If the range, which is required to be pressure-resistance, can be made smaller than the existing one, the cost of an apparatus can be reduced.
The high-pressure treatment apparatus of the present invention, in the first high-pressure treatment apparatus, is characterized in that transfer of the solid from the second solid reservoir to the high-pressure reactor is carried out by gravity.
With such a constitution, the structure for feeding the treatment object from the second reservoir to the high-pressure reactor can be simplified.
The high-pressure treatment apparatus of the present invention, in the first high-pressure treatment apparatus, is characterized in that at least one of the first solid reservoir and the second solid reservoir is provided with a vibrating means.
In feeding the solid in the first solid reservoir or the second reservoir, vibration prevents the solid from bridging therebetween. Thereby, the first solid reservoir or the second solid reservoir or the connecting pipe can be prevented from being clogged by the solid.
The high-pressure treatment apparatus of the present invention, in the first high-pressure treatment apparatus, is characterized in that cooling means is installed between the second sealing unit and the high-pressure reactor.
With such a constitution, even if the temperature of the high-pressure reactor side is high, the temperature of the second sealing unit side can be held low.
The high-pressure treatment apparatus of the present invention, in the first high-pressure treatment apparatus, is characterized in that a ball valve is used at least in one of the first sealing unit and the second sealing unit.
Here, the ball valve is a valve that is a spherical valve body, has a pass area identical with piping, and can dispense with grease (see Perry""s Chemical Engineers"" Handbook, Sixth Edition 6 to 61).
With such a constitution, a wide pass area of the treatment object and sealing of the high-pressure fluid can be secured. The sealing unit can be made smaller and the driving force counteracting the pressure of the high-pressure reactor is made unnecessary.
The high-pressure treatment apparatus of the present invention, in the first high-pressure treatment apparatus, is characterized in that at least one of between the first solid reservoir and the second solid reservoir and between the second solid reservoir and the high-pressure reactor is provided with a rotary feeder.
Here, the rotary feeder is one kind of powder-feeder and controls feed speed by feeding powder continuously due to rotation of rotary-vane (Edited by Kagakukogaku Kyokai, ┌Kagakukougaku Binran Revised 5th Edition┘ 871 (1988), Maruzen Publishing Co).
By installing the rotary feeder, the treatment object in the second solid reservoir can be continuously and quantitatively fed to the high-pressure reactor.
The high-pressure treatment apparatus of the present invention, in the first high-pressure treatment apparatus, is characterized in that a primary crushing means for implementing primary crushing of the solid being fed to the first solid reservoir is provided with.
As the primary crushing means, for instance, an impact crusher is preferably used. However, the primary crusher is not restricted to this and can be appropriately selected according to the treatment objects. The treatment object that has elasticity, when being low-temperature brittleness, can be crushed after lowering the temperature by use of liquid nitrogen or the like.
With such a constitution, even bulky solids can be fed to the high-pressure treatment apparatus. In addition, with a low-temperature crusher, even bulky solids having elasticity, if being substances of low-temperature brittleness, can be fed.
The high-pressure treatment apparatus of the present invention, in the first high-pressure treatment apparatus, is characterized in that between the first solid reservoir and the high-pressure reactor, measuring means for measuring the feed speed of the solid is installed.
For the measuring means, a feed speed measuring unit consisting of a detecting plate and an impact load measuring unit and a feed speed measuring unit consisting of a metering tank and a weighting level gauge can be cited.
With such a constitution, the feed amount of the treatment object can be controlled with ease to result in suppression of fluctuation of conditions such as temperature, pressure and composition inside of the high-pressure reactor. In addition, from the accumulated feed amount, the amount of remaining treatment object in the first solid reservoir or the second solid reservoir can be detected to result in an accurate detection of switching time of the operation mode of the unit.
The high-pressure treatment apparatus of the present invention, in the first high-pressure treatment apparatus, is characterized in that between the second solid reservoir and the high-pressure reactor, a screw feeder is installed.
Here, the screw feeder is an apparatus transferring continuously the crushed solid by use of rotation of a screw. By employing this, the treatment object can be smoothly and continuously fed to the high-pressure reactor.
The high-pressure treatment apparatus of the present invention, in the first high-pressure treatment apparatus, is characterized in that between the second solid reservoir and the high-pressure reactor, a vibration feeder is installed.
Here, the vibration feeder is an apparatus transferring continuously the primarily crushed solid due to vibration in an oblique direction of the vibrator. Thereby, the treatment object can be smoothly and continuously fed to the high-pressure reactor.
A second high-pressure treatment apparatus of the present invention is characterized in that it comprises a high-pressure reactor, an exterior vessel in which the high-pressure reactor is installed, object feed means for feeding a treatment object into the high-pressure reactor, reaction medium feed means for feeding a reaction medium into the high-pressure reactor, and gap pressure control means for controlling the pressure of a gap between the exterior vessel and the high-pressure reactor to be higher than that within the high-pressure reactor.
For the treatment object, not only the solid but also liquid can be used. The solid can be used in the form of slurry or melt after melting. When the treatment object is liquid, for instance, a pump or the like can be used as means for feeding.
By reducing the pressure difference of the inside and the outside of a high-pressure reactor, the strength demanded for the high-pressure reactor can be remarkably reduced. Accordingly, the high-pressure reactor is not required to be high in high-temperature strength and can have a thinner wall thickness. The pressure difference between the inside and the outside of the high-pressure reactor is preferable to be approximately 2 MPa or less, more preferable to be approximately 0.5 MPa or less.
The high-pressure treatment apparatus of the present invention, in the second high-pressure treatment apparatus, is characterized in that the gap pressure control means comprises a feeder of pressure holding fluid for feeding pressure holding fluid into the gap and a pressure controller of the pressure holding fluid for controlling the pressure of the pressure holding fluid.
With such a constitution, the gap pressure can be controlled with ease. Pressure sensors are installed to measure pressures of the inside of the high-pressure reactor and the inside of the gap to control the pressure of the pressure holding fluid based on the measured values of these sensors.
The high-pressure treatment apparatus of the present invention, in the second high-pressure treatment apparatus, is characterized in that means for controlling the temperature of the exterior vessel to be lower than that of the high-pressure reactor is installed.
For instance, by using liquid as the fluid within the gap, the temperature of this liquid is controlled. Thereby, the temperature of the exterior vessel can be made lower than that of the high-pressure reactor. This is particularly preferable when the temperature inside of the high-pressure reactor is high. Temperature sensors for measuring the temperatures of the inside of the high-pressure reactor and the inside of the gap are installed to adjust the temperature of the pressure holding fluid based on the values measured by these sensors.
With such a constitution, the temperature of the exterior vessel can be kept low enough to enable to use materials low in high-temperature strength and corrosion-resistance thereof for the exterior vessel. In addition, the inner wall temperature of the high-pressure reactor can be kept lower than the reaction temperature inside of the reactor to result in lowering corrosion speed of the high-pressure reactor.
The high-pressure treatment apparatus of the present invention, in the second high-pressure treatment apparatus, is characterized in that the exterior vessel is consisting of a trunk and a cover that can be opened and shut, and the high-pressure reactor is fixed to be removable to the exterior vessel.
With such a constitution, the high-pressure reactor can be replaced or repaired with ease.
The high-pressure treatment apparatus of the present invention, in the second high-pressure treatment apparatus, is characterized in that the high-pressure reactor is composed of, or the inner surface of the high-pressure reactor is lined with, one of austenite stainless steel, Ni, Zr, Ti, Ta, Au, Pt, alloys of two kinds or more thereof, and alloys of at least one kind thereof and other metals.
Depending on whether corrosion environment is oxidizing or contains chlorides, various kinds of passive materials can be used considering therange shown in FIG. 16 (M. Stern and C. Bishop, Trans. Amer. Soc. Metals, Vol. 52, p239 (1960)).
For instance, when the high-pressure reactor contains chlorides of low concentration of 100 ppb or less and the environment of which is oxidizing, austenite stainless steel is preferably used to manufacture or to line the high-pressure reactor.
For instance, when the concentration of chlorides is low such as 1% or less, Ni based corrosion resistant alloys can be preferably used to manufacture or line the high-pressure reactor.
For instance, when the concentration of chlorides is low such as 1% or less and the environment is oxidizing, Zr or Zr based alloys can be preferably used to manufacture or line the high-pressure reactor.
For instance, when the concentration of chlorides is slightly higher such as 1% or more and the environment is oxidizing, Ti or Ti based alloys can be preferably used to manufacture or line the high-pressure reactor.
For instance, when the concentration of chlorides is slightly higher such as 1% or more and the environment is oxidizing or reducing, Ta or Ta based alloys can be preferably used to manufacture or line the high-pressure reactor.
When the concentration of chlorides is high such as several % or more, Au, Au based alloys, Pt or Pt based alloys can be preferably used to manufacture or line the high-pressure reactor.
The inner surface of the high-pressure reactor that contacts with highly corrosive reactants, according to the processing environment, can be composed of metals of high corrosion-resistance to protect from corrosion.
The high-pressure treatment apparatus of the present invention, in the second high-pressure treatment apparatus, is characterized in that on the inner surface of the high-pressure reactor, ceramic material is thermally sprayed.
When the temperature inside of the high-pressure reactor is extremely high such as approximately 550xc2x0 C. or more, ceramics of excellent corrosion-resistance can be preferably thermally sprayed. The inner surface of the high-pressure reactor that contacts with highly corrosive reactants, according to the processing environment, can be coated by the ceramics of high corrosion-resistance to protect from corrosion.
The high-pressure treatment apparatus of the present invention, in the first high-pressure treatment apparatus, is characterized in that the high-pressure reactor is installed inside of the exterior vessel, and gap pressure control means for controlling the pressure inside of the gap of the high-pressure reactor and the exterior vessel to be higher than that inside of the high-pressure reactor.
With such a means, the treatment object, even when being solid, can be fed safely to the high-pressure reactor.
The high-pressure treatment apparatus of the present invention, in the first and second high-pressure treatment apparatuses, is characterized in that the reaction medium within the high-pressure reactor is in super-critical state or sub-critical state.
A method for feeding to a high-pressure treatment apparatus of the present invention, in feeding the solid from a first solid reservoir to a second solid reservoir under atmospheric pressure and in feeding the solid from the second solid reservoir to a high-pressure reactor, is characterized in that between the first solid reservoir and the second solid reservoir a first sealing unit is intervened, between the second solid reservoir and the high-pressure reactor a second sealing unit is intervened, the first sealing unit is shut and the second sealing unit is opened, and the pressure between the first sealing unit and the second sealing unit and the pressure between the second sealing unit and the high-pressure reactor decrease gradually toward the high-pressure reactor to form a pressure gradient.
With such a method, in feeding a treatment object into a high-pressure reactor, fluid can be prevented from back flow from a high-pressure reactor to a second solid reservoir.
A method of protecting a high-pressure reactor of the present invention is characterized in that in the gap between a high-pressure reactor and an exterior vessel inside of which the high-pressure reactor is installed a pressure holding fluid is filled, the pressure holding fluid is pressurized so that the pressure within the gap is maintained higher than that inside of the high-pressure reactor, and the temperature and movement of the pressure holding fluid are controlled so that the temperature of the exterior vessel is maintained lower than that of the high-pressure reactor.
Thus, a high-pressure reactor can be firmly protected.